Rotary gas pump



Feb. 6, 1934. J. sm

ROTARY GAS PUMP Filed Nov. 8, 1953 2 Sheets-Sheet l J. SIM

ROTARY GAS PUMP Feb. 6, 1934.

Filed Nov. 8, 1955 2 Sheets-Sheet 2 7 #670107": e, ,JZ L /w a: WWM

Patented Feb. 6, 1934 UNITED STATES PATENT OFFICE ROTARY GAS PUMP Application November 8, 1933, Serial No. 697,220,

and in Great Britain November 16, 1932 7 Claims.

This invention relates to gas pumps of the liquid-ring type comprising a rotary impeller having intervane cells which are alternately emptied of, and filled with, liquid in each rotation of the 5 impeller, whereby to set up pumping action which withdraws the gas or air and vapor from a vessel to be exhausted and delivers the same to atmosphere.

In contradistinction with normal rotary or senl trifugal pumps, in the pump forming the subject of this invention the pump casing rotates with the impeller. Part of the periphery of the impeller is shrouded, and a tubular scoop within the casing, having an inlet for liquid located at or near the 15 periphery of the casing, has an outlet directed into the shrouded side of the impeller, while a pipe structure extending axially of the casing is provided with gas inlet and outlet ports communicating with the impeller eye. 20 The operation is such that, in the rotation of the casing and impeller, liquid within the casing is constrained centrifugally to rotate in the form of a ring lining the casing, and that liquid entering the scoop from the ring and delivered to the shrouded side of the impeller displaces gas or air and vapor from the intervane cells of the impeller at that side to the pump outlet, and is expelled centrifugally from the impeller when it passes clear of the shrouding, whereby suction is set up in the pump '30 A liquid-ring gas pump constructed in accordance with the present invention is illustrated in the accompanying drawings in which Fig. 1 is a vertical section, and Figs. 2 and 3 are horizontal sections on the lines 22 and 33, respectively,

35 Of Fig. 1.

The liquid-ring gas pump shown comprises a cylindrical pump casing 1 mounted for rotation about a vertical axis and penetrated axially by a fixedpipe 2 pr sen in at its lower end inlet and outlet passages 3, 4, respectively, provided at their lower ends with diametrically opposed ports 5, 6 respectively, located in the plane of rotation of a vaned impeller '7. A fixed disc 8 located within the casing 1 and forming a covering wall for the impeller 7 is provided with a depending arcuate 13 to which the impeller '7 is attached and from which depends a central boss 14 coupled to the armature shaft 15 of a driving motor disposed within a casing 16 surmounted by the pump. A cover 17 detachably fitted to the casing 1 presents a hollow trunnion 18 penetrated by the pipe 2 and journalled in a roller bearing 19 mounted in a cover 20 applied to a stationary casing 21 surrounding the pump casing 1 and open to the atmosphere.

The disc 8 is unitary with a central boss 22 surrounding and fixed to the inner end of the pipe 2 and provided with ports 5, 6 registering, respectively, with the ports 5, 6. A downward extension 23 of the boss 22 is centered in a bearing 24 fitted into the boss 14.

The lower end portion of the pipe 2 is provided with a diametral partition 25 separating the inlet and outlet passages 3, 4, the passage 3 being continuous with the upper portion of the pipe which merges at its upper end into an inlet branch 26. The outlet passage 4 communicates with the interior of the casing 21, i. e., with the atmosphere, by way of ports 27, 28 formed, respectively, in the pipe 2 and in the pump casing cover 17, the port 28 being located within the inner periphery of the liquid ring.

As will be evident, the inlet passage 3 communicates by way of the ports 5, 5' with the unshrouded side of the impeller 7 and the outlet passage 4 communicates by way of the ports 6, 6' with the shrouded side of the impeller 7.

The pipe 2 is integral with a flange 29 bolted to the cover 20.

Make-up sealing liquid is supplied to the pump casing 1 through a branch 30 on the upper end of the pipe 2, the pump casing 1 being initially primed with sealing liquid by way of a normally plugged orifice 30' in the upper end of the pipe 2. Excess sealing liquid is entrained by the discharged gas and discharged therewith through the port 28, being trapped in an annular gutterv 31 within the casing 21 whence it is drained away by way of a drain connection32. 10

It will readily be understood that, in the rotation of the casing 1 and impeller '7, liquid within the casing 1 is constrained centrifugally to rotate in the form of a ring lining the casing as shown by the vertical dotted lines in Fig. 1, and that liquid entering the scoop 10 from the ring and delivered to the peripherally shrouded side of the impeller 7 displaces gas or air and vapor from the intervane cells at that side to the pump outlet, and is expelled centrifugally from the impeller 7 when it passes clear of the shrouding 9, whereby suction is set up in the pump inlet.

It will be seen that the shroud flange 9 and the ported pipe 2 function, in effect, as valves which open and close the intervane cells in the rotation of the impeller. Liquid in those cells unshrouded by the flange 9 recedes centrifugally from the centre outwards and thus exercises suction effect on the port 5, passage 3, and inlet 26. As the cells pass within the confines of the shroud flange 9, they receive liquid from the scoop 10 through the spiral port 12 whereby the gas within the cells is compressed towards the centre of the impeller and finally discharged through the port 6, passage 4, and ports 2'7, 28, to atmosphere. As will be evident, the arrangement is such that the impeller cells are filled with and emptied of liquid in each rotation of the impeller.

What I claim is:--

1. A liquid-ring gas pump comprising a rotary pump casing, a vaned impeller mounted within and rotatable with said casing, said impeller having a central eye, stationary means shrouding part of the periphery of said impeller, a stationary tubular scoop within said casing, said scoop having an inlet for liquid located near the periphery of said casing and an outlet directed into the shrouded part of said impeller, and a stationary pipe structure extending axially of said casing and provided with gas inlet and outlet ports communicating with said eye.

' 2. A liquid-ring gas pump as claimed in claim 1 in which the inner end portion of the pipe structure is provided with an internal partition defining an inlet passage and an outlet passage, said inlet passage being continuous with the outer end portion of the pipe and said outlet passage merg'- ing into an outlet port communicating with the interior of the pump casing, said pump casing being provided with an outlet port to atmosphere.

3. A liquid-ring gas pump as claimed in claim 1 in which the shrouding means is constituted by a flange unitary with a slotted disc which carries the scoop.

4. A liquid-ring gas pump as claimed in claim 1 in which the shrouding means is presented by a flanged disc having a slot forming the scoop outlet, said slot so disposed that the intervane cells of the impeller passing said slot are progressively filled with liquid radially inwards.

5. A liquid-ring gas pump as claimed in claim 1 in which one end wall of the pump casing is coupled to a driving shaft and the other end wall presents a hollow trunnion penetrated by the pipe structure and a stationary outer casing in which said pipe structure is journalled, said outer casing being open to atmosphere.

6. A liquid-ring gas pump as claimed in claim 1 in which the pump casing is enclosed in a stationary outer casing formed internally with an annular gutter adapted to receive excess sealing liquid discharged from the pump casing and fitted with a drain outlet.

7. A liquid-ring gas pump as claimed in claim 1 in which he shrouding means is presented by a flanged disc unitary with a ported boss attached to the inner end of the pipe structure and presenting a journal extension centred in a bearing mounted in the adjacent end wall of the pump casing.

JAMES SIM. 

